Taken together, impairment, disability and handicap changes define the stages of ALS in a manner similar to the interaction between the Kurtzke Functional Scales and the Kurtzke Expanded Disability Status Scale in multiple sclerosis (MS).20 Further research is required to dissect the relative contributions of impairment, disability and handicap to the clinical state of the patient and, in turn, the effect of this clinical state on the well-being of the patient.